NCERT Class 8 Science Chapter 11 Force and Pressure

NCERT Class 8 Science Chapter 11 Force and Pressure Solutions to each chapter is provided in the list so that you can easily browse through different chapters NCERT Class 8 Science Chapter 11 Force and Pressure and select need one. NCERT Class 8 Science Chapter 11 Force and Pressure Question Answers Download PDF. NCERT Class 8 Science Solutions.

NCERT Class 8 Science Chapter 11 Force and Pressure

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Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 8 Science Solutions are part of All Subject Solutions. Here we have given NCERT Class 8 Science Chapter 11 Force and Pressure and Textbook for All Chapters, You can practice these here.

Force and Pressure

Chapter: 11

NCERT TEXT BOOK EXERCISES

Q. 1. Give two examples each of situations in which you push or pull to change the state of motion of objects.

Ans. (i) We push the door to open it.

(ii) We pull the desk to change its position.

Q. 2. Give two examples of situations in which applied force causes a change in the shape of an object.

Ans. When we apply force on clay with our fingers, its shape gets changed, when we press balloon with our hands, its shape get changed.

Q.3. Fill in the blanks in the following statements:

(a) To draw water from a well we have to _________ at the rope.

Ans. pull.

(b) A charged body _________ an uncharged body towards it.

Ans. attracts.

(c) To move a loaded trolley we have to _________ it.

Ans. push it.

(d) The north pole of a magnet __________ the north pole of another magnet.

Ans. repels.

Q. 4. An archer stretches her how while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the  following terms:

muscular, contact, non-contact, gravity, friction, shape, attraction

(a) To strecth the bow, the archer applies a force that causes a change in its __________.

Ans. shape.

(b) The force applied by the archer to stretch the bow is an example of _________ force.

Ans. muscular.

(c) The type of force responsible for a change in the state of motion of the arrow is an example of a _________ force.

Ans. contact.

(d) While the arrow moves towards its target, the forces acting on it are due to _________ and that due to _________  of air.

Ans. gravity and friction.

Q. 5. In the following situations identify the agent exerting a force and the object on which it acts. State the effect of the force in each case.

(a) Squeezing a piece of lemon between the  fingers to extract its juice.

Ans. Agent are fingers, object is lemon, effect of force can be observable in form of lemon juice being expelled by squeezing.

(b) Taking out paste from a toothpaste tube.

Ans. Agent is hand of the person squeezing the tube, object is toothpaste tube and effect of the force can be observed as the paste coming out of the tube.

(c) A load suspended from a spring while its bother end is on a hook fixed to a wall.

Ans. Agent is the load suspended, object is the spring and effect can be seen in the form of elongation of spring on suspension of load.

Q. 6. A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?

Ans. The force due to hammering causes the change in the shape of the iron and iron can be moulded in the shape of the required tool.

Q. 7. An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?

Ans. Electrostatic force.

Q. 8. Name the forces acting on a plastic bucket containing water held above ground level in your hand. Discuss why the forces acting on the bucket do not bring a change in its state of motion.

Ans. Forces acting on the plastic bucket:

(i) Force of gravity acting downward.

(ii) Muscular force of arms acting upward.

The two forces do not bring any change in state of motion of bucket because both forces are equal and act in the opposite directions and thus cancel each other’s effect.

Q. 9. A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after I leaving the l launching pad.

Ans. When a rocket leaves launching pad, following forces act on it.

(i) Gravitational force of earth (downward).

(ii) Propelling force of gases emitted by combustion of fuels (upward).

Q. 10. When we press the bulb of a dropper with its nozzle kept in water, air in the dropper is seen to escape in the form of bubbles. Once we release the pressure on the bulb, water gets filled in the dropper. The rise of water in the dropper is due to:

(a) pressure of water.

(b) gravity of the earth.

(c) shape of rubber bulb.

(d) atmospheric pressure.

Ans. (d) atmospheric pressure.